Email Text Encoding: Base64? Unicode?

Does anyone know what text encoding is used for Gmail, and if it can be changed in preferences?

One of the mail lists I subscribe to doesn't seem to like messages sent from Blackberry phones in Base64 encoding; in the digests, the messages come through as gobbledygook. A test message sent from one of the subscribers who recently got a Droid did the same, by reports from some digesters.

When I get home next week and start playing with my Droid (it's sitting on my desk at home, delivered four days ago), I'd like to be able to send mail to the list without jacking up the digests. Can it be set to Unicode or something similar that won't hose the digest compiler?